Operating Costs. Topic 3 - Audio 33. Fan outdoors mounted within a cosmetic enclosure

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1 Topic 3 - Audio 33 Although radon fans have improved over the years, they can still be abused. Locate fan in a location where all portions of fan and vent pipe that is under positive pressure is not in a location where leakage of radon could enter living space. Good Locations: In unoccupied attics Outside of the house In garage with no living space above it Bad Locations: In crawl space beneath house In basement In occupied attic In garage where there is living space above it. Fan outdoors mounted within a cosmetic enclosure Fan in attic. Note fittings for easy replacement Locate fan where it can be accessed for maintenance. Install fittings that allow for removal (don t glue fan to pipe!) Don t bury fan below grade (even if you do use a box) EPA Radon Mitigation Standards. Section Radon vent fans used in active soil depressurization or block wall depressurization systems shall not be installed below ground nor in the conditioned (heated/cooled) space of a building, nor in any basement, crawlspace, or other interior location directly beneath the conditioned spaces of a building. Acceptable locations for radon vent fans include attics not suitable for occupancy (including attics over living spaces and garages), garages that are not beneath conditioned spaces, or on the exterior of the building. 1

2 Topic 3 - Audio 34 Discharge of system can have high levels of radon Terminate at a location where gases will not re-enter house or expose people in at grade level or in adjacent homes. Minimum of 10 feet above ground level Minimum of 10 feet away from any opening that is less than 2 feet below the discharge Minimum of 10 feet from any private or public access Minimum of 10 feet from any adjacent building Above eave of roof Keep away from swamp coolers and other powered intakes. EPA Radon Mitigation Standards. Section To prevent re-entrainment of radon, the point of discharge from vents of fan-powered soil depressurization and block wall depressurization systems shall meet all of the following requirements: (1) be above the eave of the roof, (2) be ten feet or more above ground level, (3) be ten feet or more from any window, door, or other opening into conditioned spaces of the structure that is less than two feet below the exhaust point, and (4) be ten feet or more from any opening into an adjacent building. The total required distance (ten feet) from the point of discharge to openings in the structure may be measured either directly between the two points or be the sum of measurements made around intervening obstacles. Whenever possible, the exhaust point should be positioned above the highest eave of the building and as close to the roof ridge line as possible. Discharge of exterior system. Do not discharge under soffit. Take around gutter. Discharge through roof 2

3 Topic 3 - Audio 35 Radon Vent Piping: Must be well sealed prime and glue fittings Must be able to able to withstand moisture (condensation) Interior Plastic (PVC or ABS) RMS allows thin wall (schedule 20) - code violation in some areas Must be schedule 40 when routed through garages. Exterior Plastic (PVC or ABS) must be at least schedule 40 Oversized commercial grade downspout often used above fan-seal joints. Size Typically 4-inch but based upon diagnostics and experience The larger the diameter, the easier for air to flow as well as reduces noise. See pipe sizing information in appendix. Moisture Air from soil will be humid. As pipe runs through cold space condensation can occur. Condensation must be able to drain back to collection point NO TRAPS and DO NOT Cut FLOOR JOISTS!!!! Mount fan vertically so condensate can drain down through casing. 3

4 Topic 3 - Audio 36 Interior Routing Pros Can allow system to be more hidden Less problem with condensation Cons Air noise can be heard if pipe diameter too small or pipe not insulated Can be more expensive to install Can take up closet space Exterior Routing May be most practical way for exterior foundation drain systems Less expensive Faster Pros Cons Can be unsightly Can have more condensation problems if water separators or insulated pipe not used in certain areas. Neighbors may complain about noise o exposure Interior Routing Can be hidden in closets Less noticeable Be careful of air noise Exterior Routing Less expensive More noticeable Fan can be mounted in enclosure to improve looks. Take precautions against freezing in cold climates. 4

5 Topic 3 Audio 37 Occupancy Separations (Fire Walls) Wall between the interior of the home and the garage is a fire resistant wall. Ceilings can also be fire rated, especially where there are townhomes with common attics. Floors separating stacked apartment units are also fire rated. Routing plastic pipe through these walls can reduce their rating which is a severe code violation. Use Plastic Pipe Devices to maintain integrity of fire wall. Purchase approved assemblies. Consist of metal collar that fits around pipe and contains a material that will swell and choke off pipe and opening in the event of a fire. Install per manufacturers recommendations and local code practices. Internal knife gate styles with external fusible links not recommended because of potential corrosion due to humidity of air stream. Fire Collar Specify pipe diameter and fire rating needed (Drawing compliments of Professional Discount Supply) Note some areas may require fire collars on both sides of wall. 5

6 Topic 3 - Audio 38 Exterior Systems In cold climates a significant amount of water can condense inside pipe. Water can freeze in pipe. When it thaws, chunks can drop into fan and lock it up. Locked fan will get hot thermal overload switched (in fan) will shut fan off, until it cools and then start back up. Cycling can cause bearing failure. Water separators on discharge can help remove condensation as well as prevent ice chunks from dropping into fan. If using downspout above fan Additional condensation can occur if it is metal. Plastic downspout can be used. Use water separator. If using than one length of downspout Fit upper section into lower section so water will drain back down rather than leak out at joint (just like a regular downspout) If you do it the opposite way, water will freeze on outside of lower section and has been known to pull system off wall due to weight of ice. Interior Systems Insulate pipe in cold areas Insulated flex duct slipped over pipe Also useful in reducing noise in portions of pipe in living spaces. Pre-insulated pipe available from some suppliers. 6

7 Topic 3 - Audio 39 Active soil depressurization systems can have fairly high concentrations of radon in them. Keep away from openings to home. Discharged air can be humid Avoid air striking building components where moisture can cause damage. In cold climates don t impact cold surfaces where ice can form. Rain caps can force radon back towards house. A properly installed system will handle far more water from condensation of soil humidity than the amount of rain that will fall down discharge. Use water separator at fan instead. Discharge air is mean annual temperature, so in cold climates the air is nice and warm. Birds, squirrels, etc. like to fly down discharge. Tough on birds and system! Install ¼-inch screen in discharge. To keep critters out. Pre-made fittings can be obtained, or put coupling on discharge with screen placed between coupling and pipe. Be sure you start up fan before installing screen on discharge to clear out debris. Otherwise, bits of attic insulation or PVC shavings will rise up, lodge against screen and shut off airflow. 7

8 Topic 3 - Audio 40 Low voltage Class II package avoids need for electrician in certain code jurisdictions. Active soil depressurization systems need appropriately sized fans to capture the radon laden soil gas before it enters the home. Here are some key characteristics of fans rated for radon service. Must be able to draw air out from foundation at a faster rate than is supplied to it. Have sufficient vacuum producing capability for the volume of air needed to be moved to not be overcome by negative pressures in home. Be capable of handling damp air and even condensate load. Mount vertically. Most fans are inline centrifugal fans Wattages: Some are packaged as low voltage systems that can be plugged into wall with class II wiring to fan up to 100 feet away from combination power supply/indicator. UL or CSA listed Comply with local codes with respect to wiring fans. Must be rated for location they are installed. EPA Radon Mitigation Standards: Wiring for all active radon mitigation systems shall conform to provisions of the National Electric Code and any additional local regulations Wiring may not be located in or chased through the mitigation installation ducting or any other heating or cooling ductwork Any plugged cord used to supply power to a radon vent fan shall be no more than 6 feet in length No plugged cord may penetrate a wall or be concealed within a wall Radon mitigation fans installed on the exterior of buildings shall be hard-wired into an electrical circuit. Plugged fans shall not be used outdoors If the rated electricity requirements of a radon mitigation system fan exceeds 50 percent of the circuit capacity into which it will be connected, or if the total connected load on the circuit (including the radon vent fan) exceeds 80 percent of the circuit's rated capacity, a separate, dedicated circuit shall be installed to power the fan An electrical disconnect switch or circuit breaker shall be installed in radon mitigation system fan circuits to permit deactivation of the fan for maintenance or repair by the building owner or servicing contractor (Disconnect switches are not required with plugged fans). Picture: Compliments of Professional Discount Supply 8

9 Topic 3 - Audio 41 Fan selection is based on permeability of aggregate which is a function of building practices in different areas. Radon fans can typically deliver 0.5 to 1-inch of water column at air flows of CFM. Static pressure is the pressure that a fan can overcome for a specific air flow. Resistance to be overcome is a function of resistance of subgrade materials and vent piping. As air flow goes up, ability to produce vacuum goes down (Air flow and differential pressure are inversely related). 3-inch pipe is considered minimum size. In difficult to mitigate houses, it may be better to add more suction points than to increase fan size. Radon Fan Characteristics: Balanced motor and impeller Ability to handle moist air streams and condensation Sealed bearings Install vertically Life expectancy: 10 years continuous service Thermal overloads to protect motor As long as fan still runs the radon will continue to be controlled unless the home is added onto. Failures: Moisture in bearings (run all the time) Water in terminal box - secure gasket on lid. 9

10 Topic 3 - Audio 42 Pipe Supports Horizontal Supports 1 every 6 feet Plumbers tape (plastic or metal) Specialty hooks Vertical Supports 1 every 8 feet Plumbers tape fastened to wood block anchored to wall Metal clamps for high traffic areas Metal straps for downspout Label Pipe At every floor it is visible (including the attic) Label should read Radon Reduction System It would be good to include other information see sample below Breaker for circuit that powers fan to be labeled in panel EPA Radon Mitigation Standards, 16.4 A system description label shall be placed on the mitigation system, the electric service entrance panel, or other prominent location. This label shall be legible from a distance of at least three feet and include the following information: "Radon Reduction System," the installer's name, phone number, and RCP Identification Number, the date of installation, and an advisory that the building should be tested for radon at least every two years or as required or recommended by state or local agencies. In addition, all exposed and visible interior radon mitigation system vent pipe sections shall be identified with at least one label on each floor level. The label shall read, "Radon Reduction System." 10

11 Topic 3 - Audio 43 A system performance indicator is required when installing active soil depressurization systems Indicate system failure Typically do not measure radon Indicate pressure or air flow of system when it was installed Change in vacuum or air flow could indicate failure. Indicator to be labeled as to what measured variable was at time of installation Guidance should be given on interpretation. Inclined Manometer Can mount device on wall and run tubing to suction piping several feet away U-Tube Mounts directly on suction pipe with small hole drilled for tube EPA Radon Mitigation Standards 16.1 All active soil depressurization and block wall depressurization radon mitigation systems shall include a mechanism to monitor system performance and warn of system failure. The mechanism shall be simple to read or interpret and be located where it is easily seen or heard by building occupants and protected from damage or destruction Electrical radon mitigation system monitors (whether visual or audible) shall be installed on nonswitched circuits and be designed to reset automatically when power is restored after service or power supply failure. Battery operated monitoring devices shall not be used unless they are equipped with a low power warning feature Mechanical radon mitigation system monitors, such as manometer type pressure gauges, shall be clearly marked to indicate the range or zone of pressure readings that existed when the system was initially activated. 11

12 Topic 3 - Audio 44 Caulking Slab Improves System Performance Joints closest to suction points are the most critical Placing suction point in unfinished area allows access to this joint. In most cases it is not necessary to remove carpet or walls to access joints Exception: where slab is not reinforced and a huge crack appears. Dirt lines on carpet may show over time as air continues to be drawn down through carpet. Use a polyurethane caulk Floor-to-Wall Joints Expansion joints Cut expansion joint flush with floor, brush and caulk over Up on wall and out on floor about 3/8-inch Tool in with back of caulk tube One 11 ounce tube/8 feet Cold joints Brush and caulk Tool caulk into joint with backside of spent tube or piece of cardboard One 11 ounce tube per 12 feet Canal Drains Serve as canal for collection and diversion of water to sump Place backer rod halfway down canal Allows for water passage both above and below baker rod Caulk over rod MAINTAIN ABILITY FOR CANAL TO DIVERT SURFACE WATER Floor Cracks Typically are not a major opening Where no re-wire is used, slabs may have very large cracks and may require carpet removal and sealing (very rare). If you caulk floor cracks Grind out crack and use a gun grade caulk Flowable caulk may drain into subgrade Use smoke bottle to determine where sealing is needed 12

13 Topic 3 - Audio 45 Reading Assignment: US EPA Radon Mitigation Standards - Section 14.5 Floor Drains: If suction impacts utility trench, air could be pulled down drain (via slip joint). Verify need with smoke bottle with system both On and Off. Special traps can be places within floor drains that stop air but let water drain properly. Same drains can also be used on sump lids, if surface water needs to drain into sump. Block Walls (See earlier discussion) Triple expanding foam Caulk at edge of full sill plate Wall Penetrations Permanent Seal: Use Polyurethane Posts on sub-grade pads (drill and foam) Tub & Toilet Use silicon Non-Permanent: Use Silicon Toilet Tub Sump lid 13

14 Topic 3 - Audio 46 Large leaks in system could cause combustion appliances to backdraft. Good sealing reduces potential Check draft of combustion appliances Especially with marginal flues EPA Radon Mitigation Standards Section Close all windows and doors, both external and internal. 2. Open all HVAC supply and return air duct vents/registers. 3. Close fireplace and wood stove dampers. 4. Turn on all exhaust and air distribution fans and combustion appliances EXCEPT the appliance being tested for backdrafting. 5. Wait 5 minutes. 6. Test to determine the indoor-outdoor pressure differential in the room where the appliance being tested is located. If the pressure differential is a negative 5 Pascals or more, assume that a potential for backdrafting exists. 7. To begin a test for actual spillage of flue gases, turn on the appliance being tested. (If the appliance is a forced air furnace, ensure that the blower starts to run before proceeding.) 8. Wait 5 minutes. 9. Using either a smoke tube or a carbon dioxide gas analyzer, check for flue gas spillage near the vent hood. 10. Repeat steps (4) through (9) for each natural draft combustion appliance being tested for backdrafting. Seasonal and extreme weather conditions should be considered when evaluating pressure differentials and the potential for backdrafting Immediately after installation and activation of any active (fan-powered) sub-slab depressurization or block wall depressurization system in buildings containing natural draft combustion appliances, the building shall be tested for backdrafting of those appliances. Any backdrafting condition that results from Suggestion: Backdrafting can occur after installation when system is breached Verify existence of CO monitors Offer CO monitors 14

15 Topic 3 - Audio 47 Performance indicator provides information (suction pressure or amp style gauge) The ability to measure air flow is very helpful Having noted post-mitigation values of suction and air flow provides a valuable reference. Check for obvious Fan off or on switched or GFI tripped circuit Vac Air Flow Amp Reason Explanation Blocked Discharge Blocked Suction Broken discharge pipe Excess inlet air Dead fan Blockage or restriction in discharge creates backpressure. This increases pressure in suction piping (i.e., lose vacuum) and decreases air flow. Check for: ice, birds, nest, debris behind screen A blocked or restricted suction (assumes restriction is below point of where vacuum measurement is made) reduces available air to suction side of fan. This causes fan to create higher vacuum in pipe between fan and restriction. Check for water in pit or sub-grade, suction pipe has fallen into bottom of pit. A broken discharge pipe makes it easier for fan to exhaust air, so air flow rate increases. Vacuum can go up or down, but most likely will go up due to lower back pressure. A broken suction pipe allows additional air into suction of system (air flow increases) making it harder for fan to draw vacuum (vacuum decreases). Check for broken suction pipe, excess air under slab (permeable soils-wind), SMD plastic pulled up. With fan off or burned out, no air will be moving and therefore no vacuum, no air flow and no power draw. 0 0 Max Locked impeller Because impeller is not turning no air will be flowing and no vacuum created. However, power will be at maximum. 15

16 Topic 3 - Audio 48 Sub-Membrane Systems Too much air: Plastic is not sealed at foundation walls or riser Air is being drawn through a void in foundation Find excess air sources with smoke gun and seal them before increasing fan size Too little air: A blockage has occurred in pipe. Debris left in pipe, or icing has occurred in discharge - Find blockage and repair. Sub-Slab Systems Too much air: Fan has insufficient capacity, or there is too much leakage from the outside grade or open areas inside the foundation - Try to find excess air sources with smoke gun and seal them before changing fan. Too little air: A blockage has occurred in pipe. Debris left in pipe, or icing has occurred in discharge - Find blockage and repair. Low or no sub-slab vacuums: Fan is too small either from an air or vacuum standpoint. An additional suction point is needed. A large opening for air entry is between the suction point and the measurement location. Pit was not dug out well enough. HVAC system is over powering building. Sump and Drain Depressurization Systems Too much air: Sump has not been sealed or removed for maintenance - Install lid with bold warning label A soak-away is open to the air - Inspect check valve or look for additional soak-away There are other pipes connected to drain such as downspouts - Locate and isolate Drains are connected to a large storm drain - Install check valve or abandon approach Block Wall Depressurization Too much air: Large leakage areas at block tops, wall penetrations, or even wall surfaces - Locate and seal Poor communication to some walls: Obstructions to air flow such as pilasters, bond beams, lintels - Add additional suction points or jumpers 16

17 Topic 3 - Audio 49 If a forced air system exists in the building always check to see if ductwork is buried in sub-grade. Supply Ducts Under Slab: Supply is the positive pressure side of Forced Air Unit (FAU) When FAU OFF, leaks in ductwork provide a pathway. When FAU is ON leakage will be into subgrade. Return Ducts Under Slab: Watch out for this! The return duct is air being returned back to FAU. Very large negative pressure inside duct When FAU is OFF, leaks in ductwork provide pathway. When FAU is ON, soil gas is sucked into ductwork and distributed into building. Vacuum may be so large that ASD systems cannot overcome negative pressure. Remedies: Your ASD system may still work if duct effect is small Fresh air make-up may provide dilutions and reduction of negative pressure in duct. Attempt sealing near FAU cabinet Conduct radon decay product measurement to determine if air circulation is reducing radon decay products to acceptable level. Consider high efficiency filters in return duct to reduce radon decay products Abandon buried ductwork and re-duct the HVAC system Cabinet door removed to view return duct View of return duct under slab Always inspect return and supply ducts. This is an alligator that can bite you! 17

18 Topic 3 - Audio 50 See Appendix for more explanation Electrical Cost Based upon either: Wattage of fan (conservative) Actual measurements Watts = current (amps) x Line voltage (volts) Example: What is the annual operating cost for a 90 watt fan operating continuously, if electricity costs $0.07 per kilowatt hour? 90 watts x 24 hr x 365 days x 1 KW x $0.07 = $55.19 per year Day year 1000 Watts KW hr Heating/Cooling penalty due to loss of conditioned air If air from within home is drawn into ASD system, that lost air is replaced by outdoor air. Puts additional load on HVAC system Can be reduced by caulking and sealing Fairly complex equation (see additional explanation in appendix) Maintenance Fans typically have sealed bearings, so lubrication is not needed Life expectancy of fan is around 10+years if properly installed Maintenance costs is minimal for system Need to retest every two-years is to be advised. 18